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// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <array>
#include <mbedtls/cipher.h>
#include "common/assert.h"
#include "common/logging/log.h"
#include "core/crypto/aes_util.h"
#include "core/crypto/key_manager.h"
namespace Core::Crypto {
namespace {
using NintendoTweak = std::array<u8, 16>;
NintendoTweak CalculateNintendoTweak(std::size_t sector_id) {
NintendoTweak out{};
for (std::size_t i = 0xF; i <= 0xF; --i) {
out[i] = sector_id & 0xFF;
sector_id >>= 8;
}
return out;
}
} // Anonymous namespace
static_assert(static_cast<std::size_t>(Mode::CTR) ==
static_cast<std::size_t>(MBEDTLS_CIPHER_AES_128_CTR),
"CTR has incorrect value.");
static_assert(static_cast<std::size_t>(Mode::ECB) ==
static_cast<std::size_t>(MBEDTLS_CIPHER_AES_128_ECB),
"ECB has incorrect value.");
static_assert(static_cast<std::size_t>(Mode::XTS) ==
static_cast<std::size_t>(MBEDTLS_CIPHER_AES_128_XTS),
"XTS has incorrect value.");
// Structure to hide mbedtls types from header file
struct CipherContext {
mbedtls_cipher_context_t encryption_context;
mbedtls_cipher_context_t decryption_context;
};
template <typename Key, std::size_t KeySize>
Crypto::AESCipher<Key, KeySize>::AESCipher(Key key, Mode mode)
: ctx(std::make_unique<CipherContext>()) {
mbedtls_cipher_init(&ctx->encryption_context);
mbedtls_cipher_init(&ctx->decryption_context);
ASSERT_MSG((mbedtls_cipher_setup(
&ctx->encryption_context,
mbedtls_cipher_info_from_type(static_cast<mbedtls_cipher_type_t>(mode))) ||
mbedtls_cipher_setup(
&ctx->decryption_context,
mbedtls_cipher_info_from_type(static_cast<mbedtls_cipher_type_t>(mode)))) == 0,
"Failed to initialize mbedtls ciphers.");
ASSERT(
!mbedtls_cipher_setkey(&ctx->encryption_context, key.data(), KeySize * 8, MBEDTLS_ENCRYPT));
ASSERT(
!mbedtls_cipher_setkey(&ctx->decryption_context, key.data(), KeySize * 8, MBEDTLS_DECRYPT));
//"Failed to set key on mbedtls ciphers.");
}
template <typename Key, std::size_t KeySize>
AESCipher<Key, KeySize>::~AESCipher() {
mbedtls_cipher_free(&ctx->encryption_context);
mbedtls_cipher_free(&ctx->decryption_context);
}
template <typename Key, std::size_t KeySize>
void AESCipher<Key, KeySize>::Transcode(const u8* src, std::size_t size, u8* dest, Op op) const {
auto* const context = op == Op::Encrypt ? &ctx->encryption_context : &ctx->decryption_context;
mbedtls_cipher_reset(context);
std::size_t written = 0;
if (mbedtls_cipher_get_cipher_mode(context) == MBEDTLS_MODE_XTS) {
mbedtls_cipher_update(context, src, size, dest, &written);
if (written != size) {
LOG_WARNING(Crypto, "Not all data was decrypted requested={:016X}, actual={:016X}.",
size, written);
}
} else {
const auto block_size = mbedtls_cipher_get_block_size(context);
if (size < block_size) {
std::vector<u8> block(block_size);
std::memcpy(block.data(), src, size);
Transcode(block.data(), block.size(), block.data(), op);
std::memcpy(dest, block.data(), size);
return;
}
for (std::size_t offset = 0; offset < size; offset += block_size) {
auto length = std::min<std::size_t>(block_size, size - offset);
mbedtls_cipher_update(context, src + offset, length, dest + offset, &written);
if (written != length) {
if (length < block_size) {
std::vector<u8> block(block_size);
std::memcpy(block.data(), src + offset, length);
Transcode(block.data(), block.size(), block.data(), op);
std::memcpy(dest + offset, block.data(), length);
return;
}
LOG_WARNING(Crypto, "Not all data was decrypted requested={:016X}, actual={:016X}.",
length, written);
}
}
}
}
template <typename Key, std::size_t KeySize>
void AESCipher<Key, KeySize>::XTSTranscode(const u8* src, std::size_t size, u8* dest,
std::size_t sector_id, std::size_t sector_size, Op op) {
ASSERT_MSG(size % sector_size == 0, "XTS decryption size must be a multiple of sector size.");
for (std::size_t i = 0; i < size; i += sector_size) {
SetIV(CalculateNintendoTweak(sector_id++));
Transcode(src + i, sector_size, dest + i, op);
}
}
template <typename Key, std::size_t KeySize>
void AESCipher<Key, KeySize>::SetIV(std::span<const u8> data) {
ASSERT_MSG((mbedtls_cipher_set_iv(&ctx->encryption_context, data.data(), data.size()) ||
mbedtls_cipher_set_iv(&ctx->decryption_context, data.data(), data.size())) == 0,
"Failed to set IV on mbedtls ciphers.");
}
template class AESCipher<Key128>;
template class AESCipher<Key256>;
} // namespace Core::Crypto
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